1. Field of the Invention
The present invention relates generally to seismic surveys and, more particularly, to a method for communicating seismic survey data for geophysical prospect evaluation.
2. Description of the Related Art
Geophysical prospect evaluation is the process of analyzing the processed data from seismic surveys to evaluate the possible presence of hydrocarbons or other valuable mineral deposits in a prospect area. Seismic surveying is a process of analyzing underground earth formations in the prospect area for structural information that would indicate the possible presence of the mineral deposits. In seismic surveying, a seismic source is used to send acoustic waves toward the earth formations. Typically used seismic sources are vibrators on land and airguns in the water. The acoustic waves that reflect from the interfaces between the earth formations are detected with seismic receivers. Typically used seismic receivers are geophones laid out in arrays on land and hydrophones towed in streamers in the water. In addition, both geophones and hydrophones may be paired in dual sensor ocean bottom cable receivers laid on the water bottom. The number of source and receiver locations used can be quite large in any case. The time and amplitude information of the detected acoustic waves are recorded for data processing. The processed information can be used for evaluating the underground structure and possible mineral content of the prospect area.
A problem in geophysical prospect evaluation is the difficulty of gaining timely access to the seismic data. Because of the large number of source and receiver locations used to record data, seismic data sets are quite large compared to the transmission capacity of current communication means. The large size of seismic data sets slows down their transmission from those who acquire the data to those who need to evaluate the data. Today's geophysical communication environment encounters logistical issues of transmission circuit availability and size; cost for full time, dedicated, point-to-point lines with burst usage periods totaling 5% or less of the total available monthly bandwidth; long lead times to install higher bandwidth communication facilities; and the administrative and physical implementation issues associated with security at both the originating and receiving ends of the data transfer process. Additionally, the bandwidth required to transmit large seismic data volumes at optimum speeds is not practically available at reasonable costs. All these problems prevent the immediate access to speculative seismic survey data by those who wish to evaluate seismic prospects.